PreferencesManager

chrome/browser/prefs/preferences_manager.h

+// Copyright 2016 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef CHROME_BROWSER_PREFS_PREFERENCES_MANAGER_H_
+#define CHROME_BROWSER_PREFS_PREFERENCES_MANAGER_H_
+
+#include <memory>
+
+#include "base/macros.h"
+#include "services/preferences/public/interfaces/preferences.mojom.h"
+
+class PrefChangeRegistrar;
+class PrefService;
+
+namespace chrome {
+
+// Implementation of prefs::mojom::PreferencesManager that accepts a single
+// prefs::mojom::PreferencesObserver.
+//
+// After calling AddObserver PreferencesManager will begin observing changes to
+// the requested preferences, notifying the client of all changes.
+class PreferencesManager : public prefs::mojom::PreferencesManager {
+ public:
+  PreferencesManager();
+  ~PreferencesManager() override;
+
+  // Must be called when the active PrefService is being destroyed.
+  void OnProfileDestroyed();
+
+  // mojom::PreferencesManager:
+  void AddObserver(const std::vector<std::string>& preferences,
+                   prefs::mojom::PreferencesObserverPtr client) override;
+  void SetPreferences(const base::DictionaryValue& preferences) override;
+
+ private:
+  // PrefChangeRegistrar::NamedChangeCallback:
+  void PreferenceChanged(const std::string& preference_name);
+
+  // Tracks the desired preferences, and listens for updates.
+  std::unique_ptr<PrefChangeRegistrar> preferences_change_registrar_;
+  prefs::mojom::PreferencesObserverPtr client_;
+  PrefService* service_;
+
+  // Used to prevent notifying |client_| of changes caused by it calling
+  // SetPreferences.
+  bool setting_preferences_;
+
+  DISALLOW_COPY_AND_ASSIGN(PreferencesManager);
+};
+
+}  // namespace chrome
+
+#endif  // CHROME_BROWSER_PREFS_PREFERENCES_MANAGER_H_